Abstract

Transmission electron microscopy(TEM), a magnetostrictive-meter setup, and a superconducting quantum interference device magnetometer were used to investigate the microstructures, saturationmagnetostriction, and magnetic properties of bulk Fe81Ga19 and Fe73Ga19Ni8 (at. %) ferromagneticshape memoryalloys (FSMAs). In the Fe81Ga19 FSMA, after solution treatment (ST) at 1100 °C for 4 h and quenching in icebrine, the antiphase boundary segments of the D03 domain were observed in the A2 (disordered) matrix. When the Fe81Ga19 FSMA was solution treated and aged at 750 °C for 24 h and then furnace cooled (FC), the A2 + D03 phase transformed into A2 + B2 + D03structures, accompanied by coarse B2 + D03 precipitates in the A2 matrix. This result decreased the saturationmagnetostriction of the aged Fe81Ga19 FSMA. However, adding more Ni to the Fe81−xGa19Nix (x = 8 at. % Ni) FSMAs enhanced the formation of B2 + D03structures, further decreased the saturationmagnetostriction, and destroyed the ferromagneticshape memory effect in Fe73Ga19Ni8 FSMA ST, aged at 750 °C for 24 h, and FC.

[Magnets or magnetic bodies characterised by the
magnetic materials therefor; Selection of materials for their magnetic
properties, Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties]